A Database for Triticeae and Avena
The following text was omitted from the research note of S.P.
Simons and S.C. Somerville. 1988. Investigations of a
genetic instability in barley, BGN 18:37-45. The text below
is the continuation of the text on page 40.
We report that we were unable to repeat the observation made by Wise
and Ellingboe (1985) of a genetic instability in progeny derived from the
cross CI-16151 X CI-16155. We tested the stability of three different
loci and recovered no true mutants. It is difficult to reconcile our
results with those of Wise and Ellingboe (1985) other than to suggest some
environmental or genetic factor, absent in our experiment, is required to
activate the destabilizing process in these lines.
Environmental stresses have been implicated in the activation of
quiescent transposable elements (Nevers et al., 1986). Unlike the
materials we used, the barley seeds used by Wise and Ellingboe were
harvested prematurely and dried in order to reduce the generation time.
It is possible that either the premature harvest or the heat treatment may
have activated the genetic instability observed by Wise and Ellingboe
A second possible explanation for the discrepancy between the two
results is that a genetic factor required to activate the instability at
the Ml-a locus was missing in the parental lines utilized in the
experiment described in this report. Although CI-16151 and CI-156155 were
derived from the same seedstocks utilized by Wise and Ellingboe, the lines
were subjected to a generation of single seed descent to ensure the
genetic purity of the lines. A genetic factor, necessary for the
expression of the instability, may have been present in a subset of either
the CI-16151 or CI-16155 stocks, and may have been lost in this process.
In conclusion, we were unable to find evidence for an active
transposable element system in these barley lines.
We would like to thank Lisa Churgay for her help in screening the F2
populations. R. Wise provided the suggestion that the difference in
harvesting methods may account for the disparity in the two sets of
results and we appreciate his helpfulness. We would also like to
acknowledge the support of the U.S. Department of Energy (DE-AC02-76-
Michigan Agricultural Experiment Station Journal Article Number